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Post by alikat218 on Jan 11, 2019 20:47:01 GMT -5

Could be. I think that it might be some mineral that was dissolved in the obsidian, came out of solution as a gas as the obsidian gradually cooled, and then condensed out at an even lower temperature. Beats me what it is.

Can you feel it or just see it?

Ali

The most important thing is to enjoy your life - to be happy - it's all that matters. Audrey Hepburn

Post by hookedonrocks on Jan 11, 2019 22:29:58 GMT -5

I cabbed some mahogany obsidian recently and encountered bubbles that were not at all apparent on the slab that I had purchased. To the eye from a distance they aren't very noticeable, but a photo really makes them stand out:

I'm considering mixing up some blackened epoxy and filling the holes, and after curing taking off the excess with a very high grit wheel.

How common are these bubbles/cavities? Common to all obsidian?

Is this a reasonable treatment?

Should I have asked the slab seller about bubbles prior to purchasing? (Doh!)

I would of course disclose the treatment to prospective buyers.

Thanks for any guidance.

The same thing happened to me,i went to the next slab off the rock? and i was good.but your right,you can't see them till your almost to polish!

Post by opalpyrexia on Jan 17, 2019 13:43:36 GMT -5

Here's a preliminary update. Preliminary because it was mostly unsuccessful (original photo on the left):

As planned, I made a quantity of powdered obsidian from the darkest areas of a couple of pieces. The powder was a light beige and formed a "light baby diaper brown" when mixed with 330 epoxy. So I added a tiny amount of mars black to turn it slightly off-black. I applied it with a pointed stick, trying to "pat" it directly into the holes. Clearly the patting technique did not fill all of the holes and some only partially. It also left small "blisters" of epoxy over the area of each hole that required extra time on lower grit wheels (600 and 1200) than I had intended to use.

I am going to try it again but this time apply it with a gloved finger with a wiping action. That should push the epoxy in, leave little or no excess epoxy to remove and enable me to immediately see if a hole is actually filled.

I thought about using my butane torch in a manner similar to that for removing bubbles in curing epoxy, but I've decided to not do that because the "bubbles" are in the obsidian and not inside the epoxy. I also could also have vacuumed the cab since I have a vacuum pump and chamber, and I may end up doing that if the wiping action is unsuccessful.

Post by johnw on Jan 17, 2019 17:28:01 GMT -5

opalpyrexia , I did a micro-zoom on your exceptional pieces and they really don't look too bad and are a natural occurrence. Whereas if you fill the holes it is now not as nature intended it to be. I am inclined to advise go with the stone as is and concoct a story about the holes being natural 3 million plus air pockets and are rare, as was previously mentioned by stephan . Your bubbles in the mahogany obsidian are microscopic compared to the impact crater I have on Big Crazy.

End of day it's your choice, but if I'm a customer and going to fork out cold cash for a good looking cab, I want it natural and not doctored. It's like the difference between buying a genuine ruby compared to one that been baked to hell and back just to enhance the color or buying a "doctored" turquoise cab. I personally think anytime you doctor a cab, it loses value over the same natural cab.

I also believe if you tell a customer the truth, this is the way it came out of the earth they would be more inclined to buy it as opposed to hearing you say , well it had some bubbles in it but I plugged them, for which they will always be looking for the holes. Just MHO

Post by johnw on Jan 19, 2019 13:17:25 GMT -5

Each to their own I guess, but if I have to make a choice between say a heart shaped 2ct. Cubic Zirconium, being a perfect stone in every way and a heart shaped 2ct. diamond with inclusions and feathers and not a perfect white color, I would go with the diamond. One I know is real, the other, no matter how fabulous it looks, is doctored and I know it.

Post by swaver101 on Jan 19, 2019 13:38:43 GMT -5

That's funny, but also funny that you would suggest that! Rather than hiding them, I had thought about providing a sciency description that just might appeal to some people. Something along the lines of this —

"Obsidian is primarily volcanic quartz that has cooled to produce this glass-like mineral. The light colored spots are natural cavities caused when gasses that were dissolved in the molten glass naturally form tiny bubbles as it cools (sort of like the bubbles you see in a carbonated beverage)."

I don't know. I think that the number of people who would find that appealing is pretty small.

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